package com.navinfo.opentsp.platform.computing.analysis.util;
/**
 * gps纠偏算法，
 * @author Administrator
 *
 */
public class GpsTransform {
	  static double pi = 3.14159265358979324;

  //
  // Krasovsky 1940
  //
  // a = 6378245.0, 1/f = 298.3
  // b = a * (1 - f)
  // ee = (a^2 - b^2) / a^2;
	  static double a = 6378245.0;
	  static double ee = 0.00669342162296594323;

  //
  // World Geodetic System ==> Mars Geodetic System
  public static int[] transform(double wgLon,double wgLat )
  {
	  double mgLon;
	  double mgLat;
	  int[] ll =  new int[2];
      if (outOfChina(wgLat, wgLon))
      {
          mgLat = wgLat;
          mgLon = wgLon;
          ll[0] = (int)(mgLon*1000000);
          ll[1] = (int)(mgLat*1000000);
          return ll;
      }
      double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
      double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
      double radLat = wgLat / 180.0 * pi;
      double magic = Math.sin(radLat);
      magic = 1 - ee * magic * magic;
      double sqrtMagic = Math.sqrt(magic);
      dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
      dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
      mgLon = wgLon + dLon;
      mgLat = wgLat + dLat;
     ll[0] = (int)(mgLon*1000000);
     ll[1] = (int)(mgLat*1000000);
		return ll;
      
  }

  static boolean outOfChina(double lat, double lon)
  {
      if (lon < 72.004 || lon > 137.8347)
          return true;
      if (lat < 0.8293 || lat > 55.8271)
          return true;
      return false;
  }

  static double transformLat(double x, double y)
  {
      double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
      ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
      ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
      ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
      return ret;
  }

  static double transformLon(double x, double y)
  {
      double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
      ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
      ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
      ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
      return ret;
  }
}